Nonsubstituted tricyclic quinoxalinediones, 6,7-dihydro-1H, 5H-pyrido[1,2,3,-de]quinoxaline-2,3-dione and 5,6-dihydro-1H-pyrrolo[1,2,3-de-quinoxaline-2,3-dione are described in A. Richardson, JR. and E. D. Amstutz, J. Org. Chem., 25 1138 and A. Richardson, JR., ibid., 25, 2589 (1965), respectively. Amine-substituted tricyclic quinoxalinedione,6,7-dihydro-6-(di-n-propylamino)-1H, 5H-pyrido[1,2,3,-de]quinoxaline-2,3-dione is disclosed in WO 90/15058, and M. W. Moon, et al., J. Med. Chem., 35, 1076 (1992) as an example of series of imidazoquinolinones and related compounds having dopaminergic and serotonergic activities, and especially, as a selective and potent D.sub.2 agonist. The compound described there would not be expected to exhibit antagonistic activities of glutamate receptors, since, to date, none of compounds possessing cross affinities to both glutamate and dopamine receptors have been appeared.
Certain quinoxalinediones and benzo[1,2-f]qunoxalinediones have been shown to have antagonist activities against glutamate receptors including glycine modulatory site of NMDA receptors and AMPA receptors (For example, D. E. Pellegrini-Giampietro, et al., Br. J. Pharmacol., 98, 1281 (1989), M. J. Sheardown, et al., Eur. J. Pharmacol., 174, 197 (1989), Y. Yoneda and K. Ogita, Biochem. Biophys. Res. Commun., 164, 841 (1989), and M. J. Sheardown, et al., Science, 247, 571 (1990)).